Photodynamic therapy reduces bone resorption and decreases inflammatory response in an experimental rat periodontal disease model.

Abstract

OBJECTIVE: The purpose of the present study was to analyze inflammatory conditions after application of photodynamic therapy (PDT) in the gingival tissues of Wistar rats with ligature-induced periodontal disease. BACKGROUND DATA: The work investigated the effectiveness of PDT in decreasing the inflammatory response, in order to avoid bone loss. METHODS: Ligatures were positioned at the mandibular first molar of rats (n=6). After 7 days the ligatures were removed and the animals were divided into two groups, one of which received eosin, with both groups subsequently being treated by light-emitting diode irradiation. The animals were killed 7 days after the treatments, and the mandibles were histologically processed (hematoxylin and eosin stain) to assess bone loss, while gingival tissues were removed for quantification of neutrophil infiltration (using the myeloperoxidase assay) and tumor necrosis factor (TNF)-? expression (by ELISA). RESULTS: Histomorphological analysis of periodontal tissues demonstrated that PDT-treated animals presented decreased bone resorption, as well as reduced neutrophil migration and lower TNF-? expression, compared to ligatured animals treated with eosin alone. CONCLUSIONS: Within the limitations of this study, it can be concluded that PDT may be useful in the treatment of periodontal disease, because of immunomodulatory effects that decrease the inflammatory response and consequently the bone resorption.